The Gegham mountains (or Gegham Ridge; ) are a range of mountains in

Armenia Armenia, officially the Republic of Armenia, is a landlocked country in the Armenian Highlands of West Asia. It is a part of the Caucasus region and is bordered by Turkey to the west, Georgia (country), Georgia to the north and Azerbaijan to ...

. The range is a tableland-type watershed basin of Sevan Lake from east, inflows of rivers Araks and

Hrazdan Hrazdan ( ) is a town and urban municipal community in Armenia serving as the administrative centre of Kotayk Province, located northeast of the capital Yerevan. As of the 2011 census, the population of the town is 44,231. During the Soviet Uni ...

from north and west, Azat and Vedi rivers from south-west and Arpachai river from south. The average elevation of the Gegham mountain range is near 2500m. The range is of volcanic origin including many

extinct volcano A volcano is commonly defined as a vent or fissure in the Crust (geology), crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface. On Earth ...

es. The range is 70 km length and 48 km width, and stretch between

Lake Sevan Lake Sevan () is the largest body of water in both Armenia and the Caucasus region. It is one of the largest freshwater Alpine lake, high-altitude (alpine) lakes in Eurasia. The lake is situated in Gegharkunik Province, at an altitude of abov ...

and the Ararat plain. The highest peak of the Gegham mountains is the Azhdahak, at 3597m. They are formed by a

volcanic field A volcanic field is an area of Earth's Earth's crust, crust that is prone to localized volcano, volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. Volcanic fields usually consist of clusters ...

, containing

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

-to-

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ...

s and

cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...

s. The highland reaches a height of 1800–2000m up to 3000m in the dividing ridge.

Geological history

Volcanism in Armenia and in the Gegham mountains is related to mantle processes accompanying, but not necessarily related to the collision of the Arabian Plate with the Eurasian Plate. Unlike in other parts of the

Caucasus The Caucasus () or Caucasia (), is a region spanning Eastern Europe and Western Asia. It is situated between the Black Sea and the Caspian Sea, comprising parts of Southern Russia, Georgia, Armenia, and Azerbaijan. The Caucasus Mountains, i ...

region, the Gegham mountains have generated primarily small scale volcanoes. The Kaputan Formation (including Mt. Atis and Gtsain Ridge) from the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

has been dated at 5.7–4.6 Ma by K-Ar and is the oldest sequence in the region.

Late Pliocene Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * Late (The 77s album), ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudo ...

activity involved various

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

ic lavas (including Lchain Volcano) and subsequently, during the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matri ...

and

obsidian Obsidian ( ) is a naturally occurring volcanic glass formed when lava extrusive rock, extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Produced from felsic lava, obsidian is rich in the lighter element ...

from the Kotayk centre (Gutansar and Atis 700 ka, then associated fissure volcanoes 550–480 ka). The volcanic activity peaked round 200 ka, when most of the Gegham centres formed from trachyandesitic lavas. Aknotsasar and Sevkatar were active less than 100ka ago. The highest point is the volcano Azhdahak, elevation - 3597.3m above sea level, in the western part of the range. There is a lake in the crater of the volcano Azhdahak that is formed from melting snow. The volcanoes Spitaksar (3560 m) and Geghasar (3446 m), the former erupted 120ka ago and the latter 80-40ka, are sources of obsidian in Armenia.

Ecology

Bird fauna of Gegham mountains includes about 250 species, 70% of all Armenia's avifauna. The southeastern slopes of Gegham mountains contain the Khosrov Forest, planted in the 4th century by Khosrov I and converted into a state park in 1958. The Gegham mountains are one of the primary presences of the vavilovia (''Lathyrus formosus'') around Mount Sevsar. Another species '' Poa greuteri'' is endemic in the area.

Rock carvings

Stonegrave Petroglyph Swastikas from Ancient Armenia VM

The Archaeological Monuments and Spaciments of Armenia Volume 6 Armenia Yerevan 1971 p 198

A great number of

petroglyph A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions ...

s - rock-carvings has been found in the area of Gegham Mountains. Most images depict men in scenes of hunting and fighting, and astronomical bodies and phenomena: the Sun, the Moon, constellations, the stellar sky, lightning, etc. Carvings of birds have attracted some archeological interest.

Gallery

File:Gegham Mountains 1.jpg File:Gegham Mountains 4.jpg File:Geghama mountains from Tar mount - panoramio.jpg File:Geghama range Emma YSU (5).jpg File:Geghama range Emma YSU (7).jpg File:Geghama range Emma YSU (8).jpg File:Գեղամա լեռները, Հատիսը, Գութանասարը Արա լեռից.jpg Armaghan"> File:Armaghan 02.jpg File:Armaghan mount crater (2829m).JPG Azhdahak"> File:-Աժդահակ S-N 03.jpg File:-Աժդահակ S-N 05.jpg File:.Աժդահակ 01.jpg File:.Աժդահակ 02.jpg Gutanasar"> File:Gutanasar, Alpian Fields 007.jpg File:Gutanasar, Alpian Fields 008.jpg File:Gutanasar, Alpian Fields 003.jpg File:Gutanasar, Alpian Fields 004.jpg File:Gutanasar, Alpian Fields 005.jpg File:Gutanasar.jpg File:Mount Gutanasar 01.jpg Gexasar"> File:.Գեղասար 03.jpg File:.Գեղասար 06.jpg File:.Գեղասար 07.jpg File:.Գեղասար 08.jpg File:.Գեղասար 13.jpg File:.Գեղասար 16.jpg Lusnalich"> File:Lusnalidj 01.jpg File:Lusnalidj 06.jpg File:Lusnalidj 02.jpg Menaksar"> File:Menaksar.jpg File:Phamb pass, view from top of mount Menaksar.jpg Sevkatar"> File:Sevkatar (Sevsar).jpg File:Սևկատար 3225մ.jpg Spitakasar"> File:-Ducks lakes S-N 01.jpg File:-Ducks lakes S-N 03.jpg File:-Ducks lakes S-N 04.jpg File:-Mets Spitakasar S-N 01.jpg File:Mount Phoqr Spitakasar from Mt. Spiakasar, 2013.06.23 - panoramio.jpg File:Mount Spitakasar, 2013.06.23.jpg

References

Sources

External links

* * {{Authority control Volcanic fields Quaternary lava domes Cinder cones Mountain ranges of Armenia Lava domes